Articles de revues : « Fluorine introduct »

1

Ye, Hao Hua, Zhan Xiong Li, Guo Qiang Chen, Shao Qiang Zhou et Jian He Cai. « Research Progress of Fluoride-Containing Acrylate Derivatives and their Application on Textile ». Advanced Materials Research 331 (septembre 2011) : 229–36. http://dx.doi.org/10.4028/www.scientific.net/amr.331.229.

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The research progress of fluorine-containing acrylate monomers and their polymers has been discussed. These monomers were classified systematically according to chemical structure, such as perfluoroalkylinyl esters monomers, methyl trifluoroacrylate monomers, and so on. The synthesis of fluorinate acrylate and their polymerization were introduced. In addition, the features of these fluoride-containing chemicals were discussed as well as their applications on fabrics and research trend.

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Zhao, Ming−Ming, Qiang Wang, Luke Saye Nenwon Krua, Rong−Nan Yi, Run−Jun Zou, Xin−Yuan Li et Peng Huang. « Application Progress of New Adsorption Materials for Removing Fluorine from Water ». Water 15, n^o 4 (7 février 2023) : 646. http://dx.doi.org/10.3390/w15040646.

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A large amount of fluorine−containing wastewater was produced with the rapid development of the industry. Excessive fluoride content in water will not only endanger ecological security but also pose threat to human health. In this study, common new adsorbents for defluorination, such as metal−based adsorbents, natural adsorbents, and nanomaterial adsorbents were reviewed for its physicochemical properties and fluorine removal efficiency. The fluorine removal mechanism of different adsorbents was introduced in detail, and the future work of the removal of fluorine using novel adsorbents was proposed. This research also introduces the application of the coupling of the adsorption method with the technology of chemical precipitation, filtration, and super−magnetic separation to treat high concentration of fluoride wastewater. A good selection of process combinations according to different needs can achieve high−efficiency defluorination in water. Finally, some existing problems of practical operation of fluorine using removal materials in the environment are summarized, hoping to contribute to the future research of fluorine removal materials.

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CHEN, Shi Yi, et Shou Ting Zhang. « Research on the Utilization and Industry Development Strategies of Fluorite Resources in China's Fluorine Chemical Industry ». Advanced Materials Research 581-582 (octobre 2012) : 142–45. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.142.

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This paper introduced fluorite resource profiles on the basis of elaborated China fluorite resource utilization status, focusing on analysis of fluorite in the fluorine chemical industry, discusses the problems of our country in the fluorine chemical industry development and firefly stone rational use of resources and the sustainable development of China's fluorine chemical industry recommendations.

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Shevelev, G. A., L. I. Vasilenko, O. M. Pakhorukova, O. N. Kosheleva, T. S. Turmagambetov, E. N. Kamenskaya, N. G. Kamensky et A. A. Dzyuba. « Emission determination of fluorine using «Grand-Potok» complex with sample injection into dc arc by spill-injection method ». Industrial laboratory. Diagnostics of materials 85, n^o 1II) (15 février 2019) : 45–49. http://dx.doi.org/10.26896/1028-6861-2019-85-1-ii-45-49.

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An additional photodetector array BLPP-369 was installed on a «Grand-Potok» complex for rapid atomic-emission determination of the fluorine concentration in fluorite samples. Introduction of fluorite samples was carried out using the spill-injection method simultaneously with high pure calcium oxide introduction using the second conveyor belt. The use of an additional photodetector array with a spectral range of 528 – 536 nm provides the possibility of expanding the spectrum of CaF molecular lines with the intensity sufficient for determination of fluorine concentrations in fluorite samples. A calibration curve for fluorine determination in a concentration range of 0.12 – 47.63% was plotted using measurement results for 200 fluorite samples. Integration of the additional photodetector array provided increased detection limit for the mass fractions of fluorine up to the maximum possible concentrations in fluorite samples. The observed effect simplifies and speeds up the analysis in the absence of the necessity to dilute the sample, thus reducing the error of measurements. The results show that there is no need to introduce additional buffer mixtures (except CaO) and use reference lines to determine the fluorine concentration, which also simplifies the measurement procedure.

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Wang, Heng, Zongzheng Cao, Yuying Zhu, Menghan Liao, Genda Gu, Qi-Kun Xue et Ding Zhang. « Tuning superconductivity of Bi₂Sr₂CaCu₂O_8+x by fluoride ion intercalation with LaF₃ gate dielectric ». Journal of Applied Physics 132, n^o 21 (7 décembre 2022) : 214301. http://dx.doi.org/10.1063/5.0121822.

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We demonstrate fluorine intercalation into Bi2Sr2CaCu2O8+x (BSCCO) flakes, as thick as 100 nm, by back-gating a single crystalline LaF3 substrate. Element-sensitive analysis not only confirms the presence of fluorine in BSCCO after gating but also reveals lateral diffusion of fluorine in BSCCO. Transport measurements further demonstrate the hole-doping effect of fluoride ions in BSCCO through effective modulation of the superconducting transitions. Our work introduces a distinct type of ions (F−) that can be intercalated into materials via solid state back-gating. It broadens the toolbox of ion back-gating and is useful for addressing exotic phenomena in the heavily hole doped regime.

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Ovrutsky, G. D. « Anti-carious effect of fluoride and secretory immunity ». Kazan medical journal 70, n^o 2 (15 avril 1989) : 121–23. http://dx.doi.org/10.17816/kazmj99911.

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It has been proved that among the factors influencing the level of dental caries and the course of this disease, the amount of fluoride that enters the body is a determining factor. Under normal conditions the main source is drinking water. The anti-carious effect is inherent in fluoride, as contained in natural waters, and artificially introduced into the water. Once in the body, fluoride is firmly attached to the enamel. At the same time in the enamel prisms represented by hydroxyapatite, one of the hydroxyl groups is replaced by fluorine, forming a hard-to-solve fluorapatite. This view of the mechanism of the anti-carious effect of fluoride is quite reasonable.

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Chao, Jilei, Ruizhi Shi, Fuqiang Chu, Yanling Guo, Qian Deng et Bing Sun. « Preparation and Properties of Hydrophobic and Oleophobic Coating for Inkjet Printing ». Coatings 13, n^o 2 (27 janvier 2023) : 286. http://dx.doi.org/10.3390/coatings13020286.

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As a functional decorative material on the surface of printing and packaging, coating plays the role of increasing gloss, wear resistance, and antifouling. It has broad application prospects in high-end printed materials such as posters, art reproductions, and maps. In this paper, dodecafluoroheptyl methacrylate was used as the fluorine-containing monomer, which was used to modify the epoxy resin and introduce fluoride first. Under the action of polymerization inhibitor and catalyst, the epoxy resin was further modified by ring opening, esterification, and neutralization with acrylic acid, maleic anhydride, and organic base as raw materials. Additionally, a fluorine-containing coating with hydrophobic and oleophobic properties was obtained finally. The effects of fluorine modification of epoxy resin and synthetic polymer were characterized by infrared spectrometer and photoelectron spectroscopy. The results showed that fluorine monomer could be successfully grafted to the molecular body of epoxy resin, and fluorine had been introduced into the surface of the polymer film. Using the contact angle tester, combined with the performance parameters such as grafting rate, thermal stability, adhesion, and gloss, the effects of the amount of fluorine monomer on the properties of the synthetic coating were discussed. The results showed that the hydrophobic and oleophobic properties of the copolymer film surface were closely related to the amount of fluorine monomer. When the molar ratio of the epoxy group to dodecafluoroheptyl methacrylate was 26:1, the mass fraction of fluorine on the film surface was 18.09%, and the contact angles of water and ethylene glycol were 121.8° and 78.2° respectively. At the same time, the printability of self-made hydrophobic and oleophobic coating was tested in this paper. The liquid repellency of inkjet printing before and after glazing and the influence of the coating on the optical properties of printed images were discussed and studied too. The results showed that the coating synthesized by the experiment was suitable for inkjet printing. It had improved the printing quality performance and the functional modification on the surface of inkjet printings, such as liquid repellency, gloss, and color reproduction.

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Huang, Junwei, Qiwu Zhang, Hongchao Li et Chao Wang. « Difficulties and Recent Achievements in Flotation Separation of Fluorite from Calcite—An Overview ». Minerals 12, n^o 8 (28 juillet 2022) : 957. http://dx.doi.org/10.3390/min12080957.

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As an important strategic non-metallic mineral resource, fluorite has been widely used in various industrial fields, such as metallurgy, optics and semiconductor manufacturing, as well as fluorine-related chemical engineering. Since the major gangue minerals of fluorite ore are silicate and carbonate ones, flotation is the main beneficiation method for the concentration. Compared with the relatively easy operation for silicate-type fluorite ore, fluorite concentration from calcite has always been the most difficult challenge in the field of mineral processing. In this review, analyses of the fundamental reasons for the difficulties of flotation separation of fluorite from calcite are performed, from the similar surface properties of both calcium minerals to the deterioration by the interference of dissolved ions in the pulp during grinding and flotation. Recent achievements in the flotation separation of fluorite from calcite as the main contents are comprehensively summarized, covering all aspects of flotation reagents of collectors, depressants and modifiers. Finally, successful examples of industrial practices forfluorite and calcite flotation separation are introduced. This overview provides a detailed and comprehensive reference source for the current research status of fluorite and calcite flotation separation, and some suggestions for future research are provided.

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Krasikova, Raisa N., et Viktoriya V. Orlovskaya. « Phase Transfer Catalysts and Role of Reaction Environment in Nucleophilc Radiofluorinations in Automated Synthesizers ». Applied Sciences 12, n^o 1 (29 décembre 2021) : 321. http://dx.doi.org/10.3390/app12010321.

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Incorporation of [18F]fluorine into PET radiotracer structure has traditionally been accomplished via nucleophilic pathways. The [18F]fluoride is generated in an aqueous solution via proton irradiation of oxygen-18 enriched water and must to be introduced into water-free organic solutions in order to generate reactive species. Thus nucleophilic 18F-fluorination traditionally included steps for [18F]fluoride concentration on the anion exchange resin, followed by removal of residual water via azeotropic distillation with MeCN, a time-consuming process associated with radioactivity losses and difficult automation. To circumvent this, several adsorption/elution protocols were developed based on the minimization of water content in traditional kryptofix-based [18F]fluoride eluents. The use of pre-dried KOH/kryptofix solutions, tertiary alcohols, and strong organic bases was found to be effective. Advances in transition metal-mediated SNAr approaches for radiolabeling of non-activated aromatic substrates have prompted development of alternative techniques for reactive [18F]fluoride species generation, such as organic solutions of non-basic alkyl ammonium and pyridinium sulfonates, etc. For radiofluorinations of iodonium salts precursors, a “minimalist” approach was introduced, avoiding the majority of pitfalls common to more complex methods. These innovations allowed the development of new time-efficient and convenient work-up procedures that are easily implementable in modern automated synthesizers. They will be the subject of this review.

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Laurema, Seppo, et Anna-Liisa Varis. « The fluoride content of Finnish honey ». Agricultural and Food Science 59, n^o 5 (1 décembre 1987) : 379–85. http://dx.doi.org/10.23986/afsci.72271.

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The content of fluoride was determined with an ion-specific electrode on 59 samples of honey from 47 localities in Finland. The concentrations ranged from 25 to 550/µg/kg and the mean for all the localities was 85.7 µg F-/kg fresh weight honey. The concentrations were lowest in eastern and northern Finland, where the amount of fluoride in the soil is small, and higher on the coast and areas where more fluoride occurs in the groundwater and bedrock. However, the highest levels of fluoride in honey were detected in the vicinity of Helsinki and some other places where the amount in the groundwater is not especially high. The higher levels in some honey may be due to fluorides introduced into the environment by the activity of man. The effects of fluoride on human health are discussed.

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Bernard-Gauthier, Vadim, Carmen Wängler, Esther Schirrmacher, Alexey Kostikov, Klaus Jurkschat, Bjoern Wängler et Ralf Schirrmacher. « 18F-Labeled Silicon-Based Fluoride Acceptors : Potential Opportunities for Novel Positron Emitting Radiopharmaceuticals ». BioMed Research International 2014 (2014) : 1–20. http://dx.doi.org/10.1155/2014/454503.

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Background.Over the recent years, radiopharmaceutical chemistry has experienced a wide variety of innovative pushes towards finding both novel and unconventional radiochemical methods to introduce fluorine-18 into radiotracers for positron emission tomography (PET). These “nonclassical” labeling methodologies based on silicon-, boron-, and aluminium-18F chemistry deviate from commonplace bonding of an [18F]fluorine atom (18F) to either an aliphatic or aromatic carbon atom. One method in particular, the silicon-fluoride-acceptor isotopic exchange (SiFA-IE) approach, invalidates a dogma in radiochemistry that has been widely accepted for many years: the inability to obtain radiopharmaceuticals of high specific activity (SA) via simple IE.Methodology.The most advantageous feature of IE labeling in general is that labeling precursor and labeled radiotracer are chemically identical, eliminating the need to separate the radiotracer from its precursor. SiFA-IE chemistry proceeds in dipolar aprotic solvents at room temperature and below, entirely avoiding the formation of radioactive side products during the IE.Scope of Review.A great plethora of different SiFA species have been reported in the literature ranging from small prosthetic groups and other compounds of low molecular weight to labeled peptides and most recently affibody molecules.Conclusions.The literature over the last years (from 2006 to 2014) shows unambiguously that SiFA-IE and other silicon-based fluoride acceptor strategies relying on18F−leaving group substitutions have the potential to become a valuable addition to radiochemistry.

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Novosyolov, A., Yu Dreer, I. Novoselova et Yu Vasina. « EFFICIENCY OF USING A TECHNOGENIC PRODUCT OF ELECTROLYTIC PRODUCTION OF ALUMINUM AS A MINERALIZER WHEN FIRING PORTLAND CEMENT CLINKER ». Bulletin of Belgorod State Technological University named after. V. G. Shukhov 7, n^o 5 (11 mai 2022) : 71–80. http://dx.doi.org/10.34031/2071-7318-2022-7-5-71-80.

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The possibility of using a technogenic product of the electrolytic production of aluminum (crushed electrodes) as a mineralizing additive during clinker burning is considered. The effectiveness of the action of the mineralizing effect of crushed electrodes and the classical mineralizer - calcium fluoride CaF2 is compared. The amount of mineralizers introduced during clinker burning is 1% according to the content of fluorine ion in the raw mixture. The effectiveness of the action of mineralizers is evaluated by determining the temperature range for the assimilation of calcium oxide into clinker minerals. Calcium oxide is completely assimilated by 1300 °C when calcium fluoride CaF2 is introduced into the raw mix. Introduction to the raw mixture of crushed electrodes contributes to the complete assimilation of calcium oxide to a temperature of 1250 °C. For additive-free clinker, complete assimilation of calcium oxide occurs at 1400°C. The assimilation of calcium oxide at lower temperatures in mixtures with the addition of calcium fluoride and crushed electrodes allows to reduce the burning temperature of the clinker to 1350 °C without losing the quality of the resulting clinker. Reducing the clinker burning temperature when using mineralizers will reduce the specific consumption of conventional fuel by about 6 kg per ton of clinker.

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Usmani, Shirin M., Linn Voss, Ina Stephan, Thomas Hübert et Erhard Kemnitz. « Improved Durability of Wood Treated with Nano Metal Fluorides against Brown-Rot and White-Rot Fungi ». Applied Sciences 12, n^o 3 (8 février 2022) : 1727. http://dx.doi.org/10.3390/app12031727.

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Low-water soluble metal fluorides such as magnesium fluoride (MgF2) and calcium fluoride (CaF2) were evaluated for decay protection of wood. Initially, the biocidal efficacy of nano metal fluorides (NMFs) against wood destroying fungi was assessed with an in-vitro agar test. The results from the test showed that agar medium containing MgF2 and CaF2 was more efficient in preventing fungal decay than stand-alone MgF2 or CaF2. These metal fluorides, in their nanoscopic form synthesized using fluorolytic sol-gel synthesis, were introduced into the sapwood of Scots pine and beech wood and then subjected to accelerated ageing by leaching (EN 84). MAS 19F NMR and X-ray micro CT images showed that metal fluorides were present in treated wood, unleached and leached. Decay resistance of Scots pine and beech wood treated with NMFs was tested against wood destroying fungi Rhodonia placenta and Trametes versicolor in accordance with EN 113. Results revealed that mass losses were reduced to below 3% in wood treated with the combination of MgF2 and CaF2. It is concluded that NMFs provide full protection to wood even after it has been leached and can be used as wood preservatives in outdoor environments.

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Jia, Jin Ming, et Bo Li. « Design of Harmful Ion Analyzer in Drinking Water ». Applied Mechanics and Materials 421 (septembre 2013) : 808–13. http://dx.doi.org/10.4028/www.scientific.net/amm.421.808.

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This paper describes the design of real-time detection of harmful ions for drinking water, mainly introduces the instrument of automatic liquid injection control mechanism and the signal sampling and processing system design and implementation. The dynamic monitoring analyzer can rapidly detect concentration domestic sewage and drinking water of various ions such as arsenic, fluorine. Test equipment mainly consists of automatic sampling software, signal sampling and processing system, wireless data transmission module. Through the instrument in practical application test of arsenic in drinking water, fluoride ion, the performance index analyzer. The detection results, simple operation, low cost, analyzer of strong pertinence, high detection precision, high degree of automation.

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Shapovalov, Yu B., V. Yu Chevychelov, V. S. Korzhinskaya, N. P. Kotova, A. F. Redkin et A. A. Konyshev. « Physical and chemical parameters of processes producing rare-metal deposits in granitoid systems with fluorine : experimental data ». Петрология 27, n^o 6 (16 décembre 2019) : 617–37. http://dx.doi.org/10.31857/s0869-5903276617-637.

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The problem of the origin of rare-metal deposits in granites is considered, taking into account the results of experimental studies, which make it possible to introduce restrictions on the interpretation of geological materials and the construction of genetic models. The role of both magmatic and hydrothermal-metasomatic factors in the formation of various types of rare-metal deposits is discussed. The saturation concentrations of Ta and Nb in granite melt significantly depend on the melt composition, varying from ~ 25 to ~ 0.1 wt.%. They depend on temperature and pressure, to a lesser extent. The partitioning of Ta and Nb between the fluorine-containing fluid and the granite melt is sharply biased in favor of the melt. The principal difference in the partitioning of W and Ta, Nb, Sn in melt granite-salt systems is shown. Fluoride water-salt phase is a very effective extractant of tungsten, while Ta, Nb and Sn completely remain in the aluminosilicate melt. The model magmatic fluid, that is in equilibrium with Li-F granite melt, is multiphase and contains significant amounts of SiO2 and fluorides of Na, Al, Li and K. The solubility of ore minerals in this fluid is insignificant, but the concentration of Nb substantially exceeds that of Ta. The concentrations of HF in high-temperature magmatic fluids were estimated that could reach ~ 0.51 M HF. The experimentally determined solidus temperatures of Li-F granites are ~ 570630C at a pressure of 100200 MPa. At T = 300550С and P = 50100 MPa the actual hydrothermal transfer of Ta and Nb is possible only by sufficiently highly concentrated solutions (fluids) of HF and, possibly, KF. At alkaline sodium solutions, hydrothermal transport of Nb is quite probable, and for Ta it is difficult, at that the solubility of pyrochlore is higher than the solubility of columbite.

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Mäntymäki, Miia, Mikko Ritala et Markku Leskelä. « Metal Fluorides as Lithium-Ion Battery Materials : An Atomic Layer Deposition Perspective ». Coatings 8, n^o 8 (8 août 2018) : 277. http://dx.doi.org/10.3390/coatings8080277.

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Lithium-ion batteries are the enabling technology for a variety of modern day devices, including cell phones, laptops and electric vehicles. To answer the energy and voltage demands of future applications, further materials engineering of the battery components is necessary. To that end, metal fluorides could provide interesting new conversion cathode and solid electrolyte materials for future batteries. To be applicable in thin film batteries, metal fluorides should be deposited with a method providing a high level of control over uniformity and conformality on various substrate materials and geometries. Atomic layer deposition (ALD), a method widely used in microelectronics, offers unrivalled film uniformity and conformality, in conjunction with strict control of film composition. In this review, the basics of lithium-ion batteries are shortly introduced, followed by a discussion of metal fluorides as potential lithium-ion battery materials. The basics of ALD are then covered, followed by a review of some conventional lithium-ion battery materials that have been deposited by ALD. Finally, metal fluoride ALD processes reported in the literature are comprehensively reviewed. It is clear that more research on the ALD of fluorides is needed, especially transition metal fluorides, to expand the number of potential battery materials available.

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Hamzah, Mohd Syahir Anwar, Nurul Amira Ab Razak, Celine Ng, Akmal Hafiszi Abdul Azize, Jumadi Abdul Sukor, Soon Chin Fhong, Mohd Safiee Idris et Nadirul Hasraf Mat Nayan. « PREPARATION OF THE ELECTROSPUN POLYVINYLIDENE FLUORIDE / POLYVINYL ALCOHOL SCAFFOLD AS A POTENTIAL TISSUE REPLACEMENT ». IIUM Engineering Journal 22, n^o 1 (4 janvier 2021) : 245–58. http://dx.doi.org/10.31436/iiumej.v22i1.1548.

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: Polyvinylidene fluoride (PVDF), a piezoelectric material, is commonly used in tissue engineering due to its potential for mimicking the electrical microenvironment of biological conditions for tissue development. In this present research, polyvinyl alcohol (PVA) was introduced into electrospun PVDF fabrication through an electrospinning process, aiming to enhance the nanofibrous membrane's biocompatibility properties by improving the hydrophilicity properties to act as an artificial tissue scaffold. The electrospun PVDF/PVA membranes are found to be optimum at a PVDF-to-PVA ratio of 90:10 due to its excellent mechanical, morphological, and hydrophilicity conductivity properties. Fourier transform infrared (FTIR) spectroscopy verified strong hydrogen bonding interaction formed between the fluorine group of PVDF with oxygen-containing in the hydroxyl group of PVA. In-vitro cell culture showed that the enhanced hydrophilic property of electrospun PVDF/PVA could significantly enhance the cell growth. These positive results indicated that the scaffold could be implemented as artificial tissue material for tissue engineering applications. ABSTRAK: Polivinilidena fluorida (PVDF) adalah bahan piezoelektrik yang biasa digunakan dalam kejuruteraan tisu kerana potensinya menyerupai keadaan persekitaran mikro-elektrik biologi bagi perkembangan tisu. Dalam penyelidikan ini, polivinil alkohol (PVA) diperkenalkan ke dalam fabrikasi pintalan-elektro PVDF melalui proses pemintalan-elektro, yang bertujuan bagi mengembangkan sifat biokompatibiliti membran nanogentian dengan meningkatkan sifat hidrofilik bagi menjadi perancah tisu tiruan. Membran pintalan-elektro PVDF / PVA didapati optimum pada nisbah PVDF-ke-PVA, 90:10 kerana sifat kekonduksian, mekanikal, morfologi dan hidrofiliknya yang sangat baik. Spektroskopi transformasi inframerah Fourier (FTIR) mengesahkan interaksi ikatan hidrogen yang kuat terbentuk antara kumpulan fluoro PVDF dengan oksigen yang terkandung dalam kumpulan hidroksil PVA. Kultur sel secara in-vitro menunjukkan bahawa sifat hidrofilik pintalan-elektro PVDF / PVA dapat meningkatkan pertumbuhan sel secara signifikan. Hasil positif ini menunjukkan bahawa perancah ini dapat digunakan sebagai bahan tisu buatan bagi aplikasi kejuruteraan tisu.

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Han, Runlin, Yuxuan Tao et Liang Zhou. « Growth Study of Hierarchical Pore SSZ-13 Molecular Sieves with Improved CO2 Adsorption Performance ». Nanomaterials 11, n^o 12 (23 novembre 2021) : 3171. http://dx.doi.org/10.3390/nano11123171.

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SSZ-13, with a unique pore structure and excellent thermal stability, showed a potential application in the adsorption and catalysis industry. In this work, Al(NO3)3 was used as an Al source to study the performance and morphology of the zeolite. The zeolite was prepared with an unconventional process by adding an Al source before the structure-directing agent and base. When inorganic oxygen-containing anions were introduced into the unconventional synthesis system, the crystals of the zeolite conform to the unconventional growth mode. The zeolites with large crystals were assembled from small unit nanocrystals. Extending the reaction time, aging time and adding fluoride ions introduced a multistage pore structure on the surface of the molecular sieve, which improved the CO2 adsorption performance. When aging for 24 h, reaction for 96 h, and the amount of fluorine added was 0.05 (F/Si), the sample had the best hierarchical pore structure. The SSZ-13 molecular sieve with an added amount of 0.1 (F/Si) has the highest CO2 adsorption performance. The adsorption amount was 4.55 mmol/g at 1 bar, which is 20.4% higher than that of zeolite SSZ-13 prepared by the conventional process.

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Zhang, Jin Rui, Jing Li et Hao Zhang. « The Modification of Natural Zeliote and its Application of the Drinking Water ». Advanced Materials Research 550-553 (juillet 2012) : 2090–93. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2090.

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As a kind of rich resources and cheap materials, natural zeolites because of its unique adsorptive characteristics were widely used in drinking water purification at present. The paper introduced the modification methods of natural zeolites mainly acid or alkali, salt, heat treatment, change silicon aluminium and etc. And introduces the application of zeolite in drinking water purification mainly include: fluoride, ammonia nitrogen and deferrizers and etc.

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Jwad, Rasha S., Alan H. C. Pang, Luke Hunter et Roger W. Read. « In Pursuit of Fluorinated Sigma Receptor Ligand Candidates Related to [18F]-FPS ». Australian Journal of Chemistry 72, n^o 3 (2019) : 213. http://dx.doi.org/10.1071/ch18510.

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This paper describes the synthesis of N-arylmethyl(1-benzyl) and N-aroyl(1-benzoyl) 4-(4-fluoromethylphenoxymethyl)piperidines as potential sigma receptor ligands analogous to the potent and highly selective sigma-1 ligand [18F]-FPS, but with enhanced or alternative binding and transport profiles. The synthesis involves N-aroylation of 4-hydroxmethylpiperidine or ethyl nipecotate, functional group manipulation of the ester group or simple activation of the hydroxyl group to introduce the phenoxy component, and subsequent functional group manipulation to reduce the amide group and introduce the fluorine into the fluoromethyl substituent. In its development, the synthesis was found to require early N-aroylation of the piperidine precursor to avoid complications due to anchimeric assistance by its nitrogen in subsequent displacement reactions. New evidence is presented on the pathway followed in a literature report of direct displacement of a benzylic hydroxyl group by fluoride ion under Appel-like conditions. Relevant to the literature report, the halide ion in the fluoromethylphenoxy 1-benzylpiperidine derivatives was surprisingly labile to hydrolytic displacement on chromatography and this aspect is worthy of further study. Moreover, the NMR spectra of the amides were complicated by geometric isomerism about the amide C(O)–N bond, but detailed analysis of spectra from 2-anisoyl derivatives allowed the assignment of diastereomeric contributors to consistent, secondary atropisomerism about the aryl–C(O) bond.

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Zhang, Dong, Kai Qiao, Jiawei Hua, Zhuang Liu, Hao Qi, Zhao Yang, Ning Zhu, Zheng Fang et Kai Guo. « Preparation of fluoroalkoxy or fluorophenoxy substituted N-heterocycles from heterocyclic N-oxides and polyfluoroalcohols ». Organic Chemistry Frontiers 5, n^o 15 (2018) : 2340–44. http://dx.doi.org/10.1039/c8qo00499d.

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Mao, Rihua, Liyuan Zhang et Ren-Yuan Zhu. « A Search for Scintillation in Doped Cubic Lead Fluoride Crystals ». IEEE Transactions on Nuclear Science 57, n^o 6 (décembre 2010) : 3841–45. http://dx.doi.org/10.1109/tns.2010.2076372.

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An effort was made to introduce scintillation light in lead fluoride crystals by selective doping. It was found that some rare earth ions doped in the lead fluoride crystal may serve as luminescence centers. The photo- and X- luminescence spectra, the decay time constants and the light outputs were measured for these doped samples. The decay time was found to be at a few milliseconds for these rare earth doped lead fluoride samples, which is too long to be useful for the homogeneous hadronic calorimeter detector concept with dual readout for future high energy physics experiments. Work to introduce scintillation in lead fluoride will continue.

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Wang, Yen-Zen, Wen-Yi Chen, Chao-Chen Yang, Chen-Lung Lin et Feng-Chih Chang. « Novel epoxy nanocomposite of lowDk introduced fluorine-containing POSS structure ». Journal of Polymer Science Part B : Polymer Physics 45, n^o 4 (2007) : 502–10. http://dx.doi.org/10.1002/polb.20892.

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Geiken, Antje, Louise Holtmann, Christian H. Splieth, Jonas Conrad, Christof E. Doerfer et Christian Graetz. « Are the Dental Guidelines for Early Dental Visits and Fluoridation Measures Supported by Pediatricians, and What Are Their Caries Prevention Efforts ? » Journal of Clinical Medicine 11, n^o 5 (22 février 2022) : 1159. http://dx.doi.org/10.3390/jcm11051159.

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(1) Background: In Germany, new recommendations for dental examinations of children and the use of fluorides have been introduced. The pediatrician (PA) should refer the patient to the dentist for dental examinations and check-ups (DEs) from the sixth month of age. Therefore, our aim was to determine with a questionnaire the extent to which PAs find DE useful, make referrals for DE and recommend fluoride. (2) Methods: The nationwide empirical survey was conducted with a self-developed and validated standardized online questionnaire. In addition to personal information, 16 items were collected. Agreement with the items was recorded using Likert scales. The data were primarily analysed descriptively. (3) Results: 696 PAs participated in the survey (age: 51.7 (8.4) years, women/men: 428/286 (61.5/38.5%). A total of 11% of PAs found referral by eruption of first tooth very important (important/neutral/unimportant: 13.8/32/43.2%), compared to 70% for complete deciduous teeth (21.3/7.3/1.4%). A total of 48.8% of PAs always recommended fluoridated toothpaste from the first tooth (often/occasionally/rarely/never: 18.3/7.8/8/17.1%) and 50.6% completely refused to recommend fluoride-free toothpaste (always/often/occasionally/rarely: 9.8/9/14.7/15.9%). A total of 44.8% never recommended the use of fluoridated toothpaste if the child cannot yet spit (always/often/occasionally/rarely: 19.2/13.9/7.8/14.3%). (4) Conclusions: Among PAs, referral to DEs was increasingly implemented as children grew older. Specific fluoride recommendations were accepted.

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Wang, Jiang, María Sánchez-Roselló, José Luis Aceña, Carlos del Pozo, Alexander E. Sorochinsky, Santos Fustero, Vadim A. Soloshonok et Hong Liu. « Fluorine in Pharmaceutical Industry : Fluorine-Containing Drugs Introduced to the Market in the Last Decade (2001–2011) ». Chemical Reviews 114, n^o 4 (3 décembre 2013) : 2432–506. http://dx.doi.org/10.1021/cr4002879.

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Sinnaeve, Davy, Abir Ben Bouzayene, Emile Ottoy, Gert-Jan Hofman, Eva Erdmann, Bruno Linclau, Ilya Kuprov, José C. Martins, Vladimir Torbeev et Bruno Kieffer. « Fluorine NMR study of proline-rich sequences using fluoroprolines ». Magnetic Resonance 2, n^o 2 (9 novembre 2021) : 795–813. http://dx.doi.org/10.5194/mr-2-795-2021.

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Abstract. Proline homopolymer motifs are found in many proteins; their peculiar conformational and dynamic properties are often directly involved in those proteins' functions. However, the dynamics of proline homopolymers is hard to study by NMR due to a lack of amide protons and small chemical shift dispersion. Exploiting the spectroscopic properties of fluorinated prolines opens interesting perspectives to address these issues. Fluorinated prolines are already widely used in protein structure engineering – they introduce conformational and dynamical biases – but their use as 19F NMR reporters of proline conformation has not yet been explored. In this work, we look at model peptides where Cγ-fluorinated prolines with opposite configurations of the chiral Cγ centre have been introduced at two positions in distinct polyproline segments. By looking at the effects of swapping these (4R)-fluoroproline and (4S)-fluoroproline within the polyproline segments, we were able to separate the intrinsic conformational properties of the polyproline sequence from the conformational alterations instilled by fluorination. We assess the fluoroproline 19F relaxation properties, and we exploit the latter in elucidating binding kinetics to the SH3 (Src homology 3) domain.

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Castillo-Toraya, Gabriela, Mesías Orozco-Ic, Eugenia Dzib, Ximena Zarate, Filiberto Ortíz-Chi, Zhong-hua Cui, Jorge Barroso et Gabriel Merino. « Planar tetracoordinate fluorine atoms ». Chemical Science 12, n^o 19 (2021) : 6699–704. http://dx.doi.org/10.1039/d1sc01325d.

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Zhang, Xiao-Feng, Peng Dong, Ying-Jie Zhang, Xi-Kun Yang, Shu-Biao Xia, Zhen-Hua Jin et Ming-Li Xu. « Pd Nanoparticles Self-Assembled on Fluorine-Modified MWCNTs as Electro-Catalysts for Methanol Electro-Oxidation ». Nano 12, n^o 03 (mars 2017) : 1750031. http://dx.doi.org/10.1142/s179329201750031x.

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Multi-walled carbon nanotubes (MWCNTs) were modified by hydrogen fluoride (HF) in a simple method. With the help of fluorine, Pd nanoparticles (3.9[Formula: see text]nm) synthesized by a one-step photochemical reduction were uniformly self-assembled on the active sites of functionalized MWCNTs and a new catalyst (Pd/HF-MWCNT) was obtained. UV–Vis absorption spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used. The results demonstrated that –F groups were introduced onto the surface of MWCNTs and C–F chemical bonds were formed. In addition, the electronic structure of Pd was changed. Pd–F coordination bond maybe formed between F atom and Pd atom. Cyclic voltammetry and chronoamperometry tests indicated that electro-catalytic activity of Pd/HF-MWCNTs catalyst for methanol in alkaline medium was about 1.6 times higher than that of the commercial Pd/C (JM) catalyst at the same condition. This new functionalized method has the advantages of simple step and safe operation. It is very significant to improve the wide application of MWCNTs and the commercial development of direct methanol fuel cells (DMFCs).

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Morita, Masato, Shigeyuki Yamada et Tsutomu Konno. « Systematic Studies on the Effect of Fluorine Atoms in Fluorinated Tolanes on Their Photophysical Properties ». Molecules 26, n^o 8 (14 avril 2021) : 2274. http://dx.doi.org/10.3390/molecules26082274.

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In this study, we synthesized a series of fluorinated and non-fluorinated tolanes, in which one or more fluorine atoms were systematically introduced into one aromatic ring of a tolane scaffold, and systematically evaluated their photophysical properties. All the tolanes with or without fluorine substituents were found to have poor photoluminescence (PL) in tetrahydrofuran (THF) solutions. On the other hand, in the crystalline state, non-fluorinated and fluorinated tolanes with one or four fluorine atoms were less emissive, whereas fluorinated tolanes with three or five fluorine atoms exhibited high PL efficiencies (ФPL) up to 0.51. X-ray crystallographic analyses of the emissive fluorinated tolanes revealed that the position of the fluorine substituent played a key role in achieving a high ФPL. Fluorine substituents at the ortho (2/6) and para (4) positions led to tight and rigid packing due to plural π–π stacking and/or hydrogen bonding interactions, resulting in enhanced ФPL caused by the suppression of non-radiative deactivation. Additionally, fluorinated tolanes with three fluorine atoms exhibited notable aggregation-induced PL emission enhancement in THF/water mixed solvents. This demonstrates that the PL characteristics of small PL materials can be tuned depending on the usage requirements.

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Walker, Mark C., Benjamin W. Thuronyi, Louise K. Charkoudian, Brian Lowry, Chaitan Khosla et Michelle C. Y. Chang. « Expanding the Fluorine Chemistry of Living Systems Using Engineered Polyketide Synthase Pathways ». Science 341, n^o 6150 (5 septembre 2013) : 1089–94. http://dx.doi.org/10.1126/science.1242345.

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Organofluorines represent a rapidly expanding proportion of molecules that are used in pharmaceuticals, diagnostics, agrochemicals, and materials. Despite the prevalence of fluorine in synthetic compounds, the known biological scope is limited to a single pathway that produces fluoroacetate. Here, we demonstrate that this pathway can be exploited as a source of fluorinated building blocks for introduction of fluorine into natural-product scaffolds. Specifically, we have constructed pathways involving two polyketide synthase systems, and we show that fluoroacetate can be used to incorporate fluorine into the polyketide backbone in vitro. We further show that fluorine can be inserted site-selectively and introduced into polyketide products in vivo. These results highlight the prospects for the production of complex fluorinated natural products using synthetic biology.

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Wang, Jiuxing, Xichang Bao, Dakang Ding, Meng Qiu, Zurong Du, Junyi Wang, Jie Liu, Mingliang Sun et Renqiang Yang. « A fluorine-induced high-performance narrow bandgap polymer based on thiadiazolo[3,4-c]pyridine for photovoltaic applications ». Journal of Materials Chemistry A 4, n^o 30 (2016) : 11729–37. http://dx.doi.org/10.1039/c6ta04059d.

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Oh, Sun Moo, Hyojoo Seo, Ka Yeon Ryu, Hoyeoul Kong et Se Hyun Kim. « Inkjet-Printed Single-Wall Carbon Nanotube Thin-Film Transistors with Fluorinated Polymer Dielectrics ». Journal of Flexible and Printed Electronics 1, n^o 2 (décembre 2022) : 235–45. http://dx.doi.org/10.56767/jfpe.2022.1.2.235.

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In this study, we introduce the organic thin-film transistors (OTFTs) employing inkjet-printed single-wall carbon nanotubes (SW-CNTs) and fluorinated acryl copolymer as a semiconductor and gate dielectric, respectively. The fluorinated acryl copolymers have the altered surface properties (such as surface energy, surface roughness, and surface potential) by changing the molar ratio of fluorinated monomer to the copolymer. Higher fluorine content led to the increase in the surface potential and the decrease in the surface energy and surface roughness. In particular, the fluorine content in the polymer surface could change the wettability and areal density of the inkjet-printed SW-CNTs. Therefore, the optimized fluorine content could provide best electrical performance with the OTFTs employing the printed SW-CNTs.

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Doboszewski, Bogdan, George W. Hay et Walter A. Szarek. « The rapid synthesis of deoxyfluoro sugars using tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) ». Canadian Journal of Chemistry 65, n^o 2 (1 février 1987) : 412–19. http://dx.doi.org/10.1139/v87-070.

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Deoxyfluoro sugars were synthesized rapidly by the reaction of trifluoromethanesulfonyl derivatives of partially protected sugars with tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) under mild conditions. The displacements occurred with inversion of configuration; fluorine has been introduced stereospecifically at each of the secondary alcoholic sites of aldohexopyranosides and in one example of a furanoid system. In some instances unsaturated compounds that contained no fluorine were produced.

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E, Yong Sheng. « Extraction and Purification of Fluorene from Wash Oil ». Advanced Materials Research 989-994 (juillet 2014) : 31–34. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.31.

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Fluorene is a basic chemical raw material, which has wide applications.This paper introduces the current fluorene technology of extration and purification from wash oil. Use the after-cut of wash oil as raw material, get fluorene by distillation and solvent crystallization. The content of fluorene is higher than 97%.The total yield is 72.24%, which is higher than current domestic production levels.

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Roy Choudhury, Angshuman, Gurpreet Kaur, Maheswararao Karanam et Sandhya Patel. « "Organic Fluorine" and its Importance in Crystal Engineering ». Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C669. http://dx.doi.org/10.1107/s2053273314093309.

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The phrase "Organic fluorine" [1] was introduced by Dunitz and Taylor in 1997 to identify the C–F bonds in organic systems. Different research groups have used the phrase to glorify or deny the influence of C–F bond in crystal lattices. Once Dunitz stated that "Organic Fluorine: Odd Man Out" and Howard et al. questioned the role of "Organic fluorine" in crystal engineering. While some researchers have refuted the role of "organic fluorine" in crystal packing; the others indicated the importance of the interactions involving the same group. A number of publications have shown the importance of "Organic fluorine" in influencing crystal packing. We have been interested in the area of weak interactions in organic solid state chemistry since 1999 [2]; especially interactions involving "Organic fluorine". The study is being conducted following a systematic approach and is still in progress. We have looked at the structures of a number if tetrahydroisoquinoline derivatives, a number of differently substituted imines, phenyleacetanilydes, benzanilides and azobenzenes [3] etc. in order to elucidate the influence of "Organic fluorine" in crystal engineering both in the presence and in the absence of strong hydrogen bonding functional groups present within the molecule. A short summary of our observations will be highlighted in the presentation.

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Sarbak, Z., et A. Pogorzelska. « Chemisorption of n-Butylamine and n-Butylmercaptan on Fluoride-Modified CoMo/Al2O3 Catalysts ». Adsorption Science & ; Technology 20, n^o 9 (novembre 2002) : 907–15. http://dx.doi.org/10.1260/02636170260555813.

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The chemisorption of n-butylamine (n-BA) and n-butylmercaptan (n-BM) on cobalt–molybdenum catalysts supported on alumina containing fluoride ions was studied. The active phases of the catalysts were introduced in two ways: either simultaneously or in two stages. It was shown that the chemisorption of n-BA increased with increasing concentration of fluoride ions, but no such relationship was observed for n-BM. The sequence in which fluoride ions and CoMo were introduced had no significant effect on the effectiveness of chemisorption.

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Susheela, Andezhath Kumaran, et Chandrawati Kumari. « Addressing Anemia in Pregnant Women and School Children through a Field Tested Novel Strategy ». Annals of the National Academy of Medical Sciences (India) 56, n^o 01 (janvier 2020) : 15–25. http://dx.doi.org/10.1055/s-0040-1710161.

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Abstract Objective To introduce a protocol for improving hemoglobin (Hb), rectifying anemia in pregnant women and school children through practice of interventions. Materials and Methods Pregnant women (n = 3,262) visiting antenatal clinics (ANCs) in two government hospitals in New Delhi were screened for Hb using a hemoglobinometer. Those anemic with Hb <12.0 g/dL were tested for fluoride in urine samples, using ion meter with F–-specific electrode. Those who are anemic with high urine fluoride level (UFL ≥1.0 mg/L) were tested for fluoride in drinking water. If water fluoride is ≥1.0 mg/L, a large number of samples were tested from the neighborhood water sources. Besides, the pregnant women were advised to use water from safe sources for cooking and drinking purposes. The pregnant women, who visited ANCs were retested for Hb and UFL during every visit and introduced to diet editing and diet counseling. Body mass index was calculated initially and prior to delivery. Delivery outcome information was collected and recorded from labor room register.Girls and boys (n = 2,420) attending six schools in the national capital were inducted in the study. “Informed consents” were obtained from the parents of the recruited children and the principal of the school. The “ascent” was obtained from the children. The protocol comprised screening for Hb and testing of fluoride levels in the urine and drinking water. Diet editing and counseling were introduced to parents/mothers during parent–teacher meetings and impact of the interventions was assessed at 1, 3, and 6 months postintervention and the recorded data were evaluated and analyzed statistically. Results It was observed that 83% of pregnant women in whom anemia was corrected delivered normal birth weight infants (2.5–3.89 kg). The 17% women in whom anemia was not corrected gave birth to low birth weight infants (1.87–2.48 kg). The school children in whom the diet editing was used as an intervention showed statistically significant enhanced Hb levels. These children did not require weekly iron and folic acid supplementation. It appears that educating parents to provide nutrient-rich food for correcting anemia seems to be an important intervention. Conclusion Fluoride from water, food, beverages, use of rock salt with high F– 157 ppm in cooking and churans when withdrawn, structural changes in the gastrointestinal system was rectified, thus enhanced absorption of nutrients. The nation should have a meaningful protocol to do justice to pregnant women and school children afflicted with anemia.

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Whelton, H. P., A. J. Spencer, L. G. Do et A. J. Rugg-Gunn. « Fluoride Revolution and Dental Caries : Evolution of Policies for Global Use ». Journal of Dental Research 98, n^o 8 (juillet 2019) : 837–46. http://dx.doi.org/10.1177/0022034519843495.

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Epidemiological studies over 70 y ago provided the basis for the use of fluoride in caries prevention. They revealed the clear relation between water fluoride concentration, and therefore fluoride exposure, and prevalence and severity of dental fluorosis and dental caries. After successful trials, programs for water fluoridation were introduced, and industry developed effective fluoride-containing toothpastes and other fluoride vehicles. Reductions in caries experience were recorded in many countries, attributable to the widespread use of fluoride. This is a considerable success story; oral health for many was radically improved. While previously, water had been the only significant source of fluoride, now there are many, and this led to an increase in the occurrence of dental fluorosis. Risks identified for dental fluorosis were ingestion of fluoride-containing toothpaste, water fluoridation, fluoride tablets (which were sometimes ingested in areas with water fluoridation), and infant formula feeds. Policies were introduced to reduce excessive fluoride exposure during the period of tooth development, and these were successful in reducing dental fluorosis without compromising caries prevention. There is now a much better understanding of the public perception of dental fluorosis, with mild fluorosis being of no aesthetic concern. The advantages of water fluoridation are that it provides substantial lifelong caries prevention, is economic, and reduces health inequalities: it reaches a substantial number of people worldwide. Fluoride-containing toothpastes are by far the most important way of delivering the beneficial effect of fluoride worldwide. The preventive effects of conjoint exposure (e.g., use of fluoride toothpaste in a fluoridated area) are additive. The World Health Organization has informed member states of the benefits of the appropriate use of fluoride. Many countries have policies to maximize the benefits of fluoride, but many have yet to do so.

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Lam, Amy C. « Defect distribution of through-Oxide boron-Implanted silicon with and without fluorine incorporation ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 1394–95. http://dx.doi.org/10.1017/s0424820100131607.

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Material defects generated during device processing can affect the performance of VLSI/ULSI devices. Ion implantation is the most common method of doping in the semiconductor industry. Implantation is usually performed with the wafers oriented 7° off the incident beam direction and through oxide to minimize the channeling effect. In order to obtain shallow p/n junctions for metal-oxide-semiconductor (MOS) devices, implantation of BF2+ molecular ions into silicon has been reported to have advantages over only B+ implantation. With the incorporation of fluorine, suppression of boron diffusion will be achieved by the emission of vacancies. However, BF2+ are heavy ions and can create considerable residual damage. Instead of BF2+ implantation, boron and fluorine implantations are done separately in our studies. As an alternative to fluorine implantation through oxide, fluorine could be introduced during thermal oxidation of silicon. Boron implantation of 3×l015/cm2 dose follows oxidation. The dosages for separate boron and fluorine implants are l×l015/cm2 and 2×l015/cm2 respectively, to attain the same elemental ratio as for BF2+ implantation.

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Nakano, Toshiki, Masao Fukuyama et Yoshimichi Ohki. « Effect of introduced fluorine on electrical breakdown characteristics of plasma polymer films. » IEEJ Transactions on Fundamentals and Materials 109, n^o 8 (1989) : 343–50. http://dx.doi.org/10.1541/ieejfms1972.109.343.

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Zabolotny, A. I. « Fluoroprophylaxis of dental caries by phonophoresis ». Kazan medical journal 67, n^o 3 (15 mai 1986) : 214–15. http://dx.doi.org/10.17816/kazmj70085.

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Our preliminary studies have shown that using ultrasound it is possible to introduce fluoride into the teeth 3 times more than by application, resulting in a significant increase in the acid resistance of enamel. The aim of the present work was to develop a technique and evaluate the anti-cariousness effectiveness of sodium fluoride ultraphonophoresis.

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Zhou, Yuqian. « Anticancer Potential of Artemisinin Derivatives Containing Fluorine Atoms ». Highlights in Science, Engineering and Technology 19 (17 novembre 2022) : 193–99. http://dx.doi.org/10.54097/hset.v19i.2850.

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Artemisinin and its derivatives were widely used in treatment of malaria in last decades years. As a natural compound extracted from Chinese herb Artemisia annua, artemisinin and its derivatives presented high cytotoxicity to tumor cell and low toxicity to human body. If this great medicine can be used in the treatment of other disease, a new treatment will be found. Many researches were carried out to confirm these compounds can be used as a new anticancer agent. Artemisinin and its derivatives presented cytotoxicity to tumor cells were confirmed by many experiments. Besides some common derivatives which were widely used in the malaria therapy, some new artemisinin derivatives were synthesized and evaluated whether these compounds can become potential anticancer drug. There is research carried out by Shu Li and others synthesized a new type of artemisinin derivatives, artemisinin derivatives containing fluorine atoms, and evaluated these new compound’s cytotoxicity to tumor cells. In this review paper, the anticancer activity of artemisinin derivatives containing fluorine atoms were introduced and its cytotoxicity against tumor cells were shown. Then, the anticancer ability of artemisinin containing fluorine atoms and other common artemisinin derivatives: dihydroartemisinin and artesunate were compared. Finally, traditional treatment of cancer, such as chemotherapy and radiotherapy were introduced in this paper. By comparing artemisinin derivatives with traditional treatment of cancer, the big cancer-fighting potential for artemisinin and its derivatives should be see and further investigated. A new series of artemisinin derivatives, compounds containing fluorine atoms have anticancer ability too. Results obtained by literature research and read show artemisinin containing fluorine atoms may be a great potential anticancer drug but still need more exploration and practice like other artemisinin derivatives.

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Li, Xiaohua, Jibao Lu, Ying Dai, Meng Guo et Baibiao Huang. « The Synthetic Effects of Iron with Sulfur and Fluorine on Photoabsorption and Photocatalytic Performance in Codoped ». International Journal of Photoenergy 2012 (2012) : 1–7. http://dx.doi.org/10.1155/2012/203529.

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The structural and electronic properties of iron-fluorine (Fe-F) and iron-sulfur (Fe-S) codoped anatase TiO2are investigated by first-principles based on density functional theory. Our results show that the formation energy of codoped system is lower than that of single-element doping, which indicates the synergic effect of codoping on the stability of the structure. Codopants introduced impurity gap states resulting in the electron transition energy reduction and thus the visible light absorption observed in the samples. It is concluded that Fe-S should be a better codoping pair because Fe-S codoping introduces extended impurity states resulting in stronger visible light absorption than that of Fe-F codoped compounds. This work gives understanding to the recent experiment and provides the evidence of choosing the more effective co-dopants in TiO2.

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Li, Qingting, Yanqiong Li et Wen Zeng. « Preparation and Application of 2D MXene-Based Gas Sensors : A Review ». Chemosensors 9, n^o 8 (14 août 2021) : 225. http://dx.doi.org/10.3390/chemosensors9080225.

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Since MXene (a two-dimensional material) was discovered in 2011, it has been favored in all aspects due to its rich surface functional groups, large specific surface area, high conductivity, large porosity, rich organic bonds, and high hydrophilicity. In this paper, the preparation of MXene is introduced first. HF etching was the first etching method for MXene; however, HF is corrosive, resulting in the development of the in situ HF method (fluoride + HCl). Due to the harmful effects of fluorine terminal on the performance of MXene, a fluorine-free preparation method was developed. The increase in interlayer spacing brought about by adding an intercalator can affect MXene’s performance. The usual preparation methods render MXene inevitably agglomerate and the resulting yields are insufficient. Many new preparation methods were researched in order to solve the problems of agglomeration and yield. Secondly, the application of MXene-based materials in gas sensors was discussed. MXene is often regarded as a flexible gas sensor, and the detection of ppb-level acetone at room temperature was observed for the first time. After the formation of composite materials, the increasing interlayer spacing and the specific surface area increased the number of active sites of gas adsorption and the gas sensitivity performance improved. Moreover, this paper discusses the gas-sensing mechanism of MXene. The gas-sensing mechanism of metallic MXene is affected by the expansion of the lamellae and will be doped with H2O and oxygen during the etching process in order to become a p-type semiconductor. A p-n heterojunction and a Schottky barrier forms due to combinations with other semiconductors; thus, the gas sensitivities of composite materials are regulated and controlled by them. Although there are only several reports on the application of MXene materials to gas sensors, MXene and its composite materials are expected to become materials that can effectively detect gases at room temperature, especially for the detection of NH3 and VOC gas. Finally, the challenges and opportunities of MXene as a gas sensor are discussed.

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Büyükyilmaz, T., et B. Øgaard. « Caries-Preventive Effects of Fluoride-Releasing Materials ». Advances in Dental Research 9, n^o 4 (décembre 1995) : 377–83. http://dx.doi.org/10.1177/08959374950090040601.

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The plaque-retentive properties of fixed orthodontic appliances result in a severe challenge on surfaces generally not susceptible to caries. Lesions may develop within a month in the absence of fluoride, and clinical studies have shown that from 50 to 75% of orthodontic patients develop decalcifications on labial surfaces during treatment. Fluoride mouthrinses reduce the occurrence, although compliance is often poor. Orthodontic bonding agents and cements releasing fluoride, which reduce the need for cooperation, have been introduced. Few clinical studies have been done to prove the cariostatic properties of fluoride-releasing materials in orthodontics. In short-term caries model studies, glass ionomers and a glass filler containing light-cured adhesive that releases relatively large amounts of fluoride have shown cariostatic properties. However, during severe challenges such as occur with orthodontic appliances, fluoride alone has limited cariostatic properties. The combination of fluoride with antimicrobial agents, and the use of acidic fluoride solutions depositing acid-resistant coatings of calcium fluoride and titanium have shown to give better clinical effects than fluoride alone during extreme conditions. Fluoride-releasing materials may therefore be considered as useful supplements to these procedures.

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Jeng, Y. R., T. T. Lin, T. Y. Wong, H. J. Chang et D. B. Shieh. « Nano-mechanical Properties of Fluoride-treated Enamel Surfaces ». Journal of Dental Research 87, n^o 4 (avril 2008) : 381–85. http://dx.doi.org/10.1177/154405910808700414.

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Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous microhardness analyses have introduced errors due to a substrate effect, and thereby could not substantiate the early loss of these deposits. To address this question, we applied Atomic Force Microscopy (AFM) and a nano-indentation technique in this study to characterize the nano-mechanical properties and topographic structure of enamel surfaces following topical fluoride treatment. The deposits were found to have a low nano-hardness and a high nano-wear depth, which explains the early loss of calcium-fluoride-like deposits. However, a 22% increase in the fluoride concentration could still be detected on the treated enamel surface following the removal of the surface deposits, justifying the long-term effectiveness of topical fluoride treatment.

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Ripa, L. W. « Dental Materials Related to Prevention— Fluoride Incorporation Into Dental Materials : Reaction Paper ». Advances in Dental Research 5, n^o 1 (décembre 1991) : 56–59. http://dx.doi.org/10.1177/08959374910050010801.

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Rather than a specific commentary to Dr. Rawls' presentation, this reaction paper discusses the general concept of fluoride addition to dental materials. The genesis of the concept is reviewed, but more important is a critique of the rationale for the deliberate addition of fluoride to dental materials. Researchers and practicing dentists should realize that if the principal reason for the addition of fluoride is to prevent dental caries, the ultimate test of that rationale is a controlled clinical trial. Thus, although a number of questions need to be answered when fluoride is introduced into dental materials, the most important is: Does it inhibit dental caries?

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Nagarajan, Rajamani, et Jyoti Pandey. « The emergence of bifunctional catalytic properties by the introduction of Bi3+ in defect fluorite-structured PrO1.833 ». Dalton Transactions 49, n^o 36 (2020) : 12707–15. http://dx.doi.org/10.1039/d0dt02121k.

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Rohym, Shaimaa Mosutafa, Asmaa Youssif Harhash et Mohammed Farid Riad. « One Year Clinical Evaluation of White Spot Lesions with Newly Introduced Resin Modified Glass-Ionomer in Comparison to Resin Infiltration in Anterior Teeth : a split mouth randomized controlled clinical trial from Egypt ». Brazilian Dental Science 24, n^o 1 (22 décembre 2020) : 13p. http://dx.doi.org/10.14295/bds.2021.v24i1.2063.

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Objective: to compare the clinical performance of newly introduced resin modified glass ionomer varnish (Clinpro™ XT) versus resin infiltration in treatment of post-orthodontic white spot lesions. Material and Methods: Six participants (70 teeth) were enrolled with post-orthodontic white spot lesions. Randomization was performed according to patient selection for the sealed envelope containing which half will receive the control (resin infiltration (ICON, DMG) and the other will receive the intervention (resin modified glass-ionomer cement varnish (Clinpro™ XT, 3M)). Follow up was done after 1 day, 1 week, 1 month, and 3 months, 6 months and 12 months. The color was assessed by spectrophotometer while the degree of demineralization was measured by Diagnodent pen 2910. Patient satisfaction was assessed using (VAS) Visual analogue scale. Results: Regarding color change, significant improvement in lightness for ICON group, while Clinpro™ XT group, the change was insignificant. The demineralization data revealed significant decrease in demineralization with resin infiltration after immediate application. Clinpro™ XT showed also significant decrease after immediate assessment and significant increase in demineralization in 6 and 12 months. Conclusion: Resin infiltration can be considered more as an alternative treatment rather than fluoride varnish. Clinpro™ XTis considered as a preventive protocol, provided that renewal application is needed after 3 months. Keywords 3M Resin cement; Resin cements; Glass ionomer cements; Fluorides; Follow up studies; Glass ionomer.

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Zhang, Yanan, Yifei Zhao, Shaobo Tan et Zhicheng Zhang. « Inserting –CHCH– into P(VDF-TrFE) by C–F activation mediated with Cu(0) in a controlled atom transfer radical elimination process ». Polymer Chemistry 8, n^o 11 (2017) : 1840–49. http://dx.doi.org/10.1039/c6py02119k.

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Articles de revues sur le sujet « Fluorine introduct »

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